This invention is generally in the field of wireless power transmitters and receivers.
A number of technologies have recently evolved for providing wireless power according to various schemes. In U.S. Pat. No. 7,027,311, systems and methods are described for wireless power systems and methods applicable to both near-field (i.e., induction) and mid-to-far-field transmission/reception of power. PowerCast (www.powercastco.com) provides a wireless receiver (‘harvester’) which is capable of converting RF energy which is either ambient due to, for example, remotely generated radio transmissions, or which can be actively transmitted by a PowerCast power transmitter. Technologies promoted by other companies (e.g. www.splashpower.com; www.wildcharge.com; www.ecoupled.com) rely primarily upon inductive coupling technologies, and may utilize an inductive pad (e.g. a ‘Splashpad’) which transmits power to receiver surfaces within the device that is to be powered. Another technology for transmitting energy over midrange distances (e.g., 9-20 feet or so) utilizes a non-radiative resonant energy transfer in which the transmitter and receiver are both tuned to the same MHz-range frequency through use of resonant beacons (e.g., Karalis, A, Joannopoulos, J. D. and Soljaci, M, Efficient wireless non-radiative midrange energy transfer (2006), also see http://en.wikipedia.org/wiki/Wireless energy transfer for review). Many of the features of the current invention are relevant to providing advantages across these different modes of providing wireless power.
Wireless technologies using either induction or mid-/far-field transmission must often address issues such as identifying devices to be charged so that these can be charged according to protocols that address their needs and capacities. In the case of inductive coupling, relative orientation of transmission/reception surfaces of devices are especially important in order to ensure correct and efficient transmission of power without shorts, surges, or ineffective transmission/reception. Some recent advances have addressed these issues in order to create devices which are more user friendly and less prone to power-transfer failure. The currently existing eCoupled technology includes an inductively coupled power circuit that dynamically seeks resonance with receiving devices: the primary circuit is able to adapt its operation to match the characteristics of the load(s) receiving circuit. The power supply circuit automatically attempts to optimize efficiency by establishing resonance between the primary and secondary coils for any given load. Communication between the transmitter and individual receiving devices can occur in real time, which allows the technology to determine not only power needs but other power characteristics of the receiving device. For example factors such as age of a battery, number of charging lifecycles, time since last charge, resistance to certain temporal charge-patterns and other characteristics of power provided, can be established in order to realize improved power supply and efficiency. Resonance-seeking strategies also allow some freedom in positioning the secondary (i.e. harvesting/receiving) relative to the primary (transmitting) components of devices while maintaining efficient transmission of electrical power. Existing inductive technologies have thereby overcome a number of traditional limitations which have previously impeded wider reliance of inductive power, such as spatial rigidity, static loads and unacceptable power losses by adapting to various loads (e.g., both low- and high-power demands), and lack of user friendliness. Using these new schemes, energy transfer efficiency can be increased over conventional inductive coupling to result in power losses as low as 10%. This makes some wireless technologies comparable to hardwired connections in terms of energy costs. Much of the safety issues have also been overcome, allowing these new inductive technologies to come much closer to, and even surpass, safety issues that match conventional ‘wired’ charging methods.
Some related technologies for transmission and reception, which can be utilized by the current invention, have been filed by Powercast and include patent applications for example, US20070010295 entitled ‘Power transmission system, apparatus and method with communication’; US20060281435 entitled ‘Powering devices using RE energy harvesting’; US20060270440 entitled ‘Power transmission network’; US20060199620 entitled ‘Method, apparatus and system for power transmission’; US20060164866 entitled ‘Method and apparatus for a wireless power supply’; US20050104453 entitled ‘Method and apparatus for a wireless power supply’; US20070117596, entitled ‘Radio-frequency (RF) power portal’; and U.S. Pat. No. 7,027,311, entitled ‘Method and apparatus for a wireless power supply’, which increases power reception by harvesting across a collection of frequencies.
Some related technologies filed by eCoupled include, for example, Inductive Coil Assembly (U.S. Pat. No. 6,975,198; U.S. Pat. No. 7,116,200; US 2004/0232845); Inductively Powered Apparatus (U.S. Pat. No. 7,118,240 B2; U.S. Pat. Nos. 7,126,450; 7,132,918; US 2003/0214255); Adaptive Inductive Power Supply with Communication (US 2004/0130915); Adaptive Inductive Power Supply (US 2004/0130916); Adapter (US 2004/0150934); Inductively Powered Apparatus (US 2005/0127850; US 2005/0127849; US 2005/0122059; US 2005/0122058. Splashpower has obtained U.S. patents such as U.S. Pat. No. 7,042,196.
Other relevant art includes, US20050194926 entitled, ‘Wireless battery charger via carrier frequency signal’; U.S. Pat. No. 6,127,799, entitled ‘Method and apparatus for wireless powering and recharging; U.S. Pat. No. 6,856,291 entitled ‘Energy harvesting circuits and associated methods; 20060238365 entitled ‘Short-range wireless power transmission and reception’; US20040142733 entitled ‘Remote power recharge for electronic equipment’; U.S. Pat. No. 6,967,462 entitled ‘Charging of devices by microwave power beaming’; U.S. Pat. No. 7,084,605, entitled ‘Energy harvesting circuit’; U.S. Pat. No. 7,212,414 entitled ‘Adaptive inductive power supply’ and describes a power transmitter which automatically adjusts its power transmission based upon sensed resonance with power receivers which it may charge; US20079178945 entitled ‘Method and system for powering and electric device via a wireless link’, describes rectifier circuitry, which may include Germanium-based rectifiers as well as those based upon silicon, gallium arsenide, and other semiconductor materials, and further utilizes a pair of diodes to permit a rechargeable battery to be charged by either a wire charging unit or signals received by the receiving antenna; US2007176840 entitled ‘Multi-receiver communication system with distributed aperture antenna’, provides for an antenna with holes configured to produce low level local power fields; U.S. Pat. No. 6,664,770 entitled ‘Wireless power transmission system with increased voltage output’, is for increased power reception and provides a radio-signal shaped to allow the receiving circuitry to operate towards this purpose; US20060204381 entitled ‘Adapting portable electrical devices to receive power wirelessly’, describes solutions for universally incorporating wireless power into devices such as cellular phones without requiring buy-in from the original equipment manufacturer (OEM). The ‘universal adapters’ suggested therein must be configured to work with various unique devices rather than truly being universal. While this solution avoids efforts for the OEM, it also requires that these ‘universal adapters’ come in as many shapes and sizes as there are batteries for the devices; WO2007084717 entitled ‘Method and apparatus for delivering energy to and electrical or electronic device via a wireless link’, describes use of a directional antenna and tracking system for adjusting the direction of the beamed energy; and, US20070021140 entitled ‘Wireless power transmission systems and methods’ describes providing wireless data and power in a factory environment. All of these patents and patent applications are incorporated by reference herein and describe technologies which will be generally treated here as wireless power systems that relate to the invention including wireless power transmission and wireless power reception.
These new wireless power systems are still hindered by a number of issues. Most embodiments oblige manufacturers to incorporate the wireless harvesting technologies into their devices, requiring ‘buy in’ from large original equipment manufacturers. Similar to the issues which have plagued utilization of compact discs, and cord adapters used by different devices, the standards, protocols, and features of wireless transmitting and receiving devices may vary greatly between companies. Systems and methods are needed for adapting wireless power technologies to ‘open’ rather than ‘closed’ platforms, allowing the adaptation of wireless power to occur without manufactures tying themselves and their product designs to particular wireless technologies, protocols, and the like. Further, when transmission of data and power are both provided in a wireless manner, the integrity of both types of transmission should be ensured, especially in the case of medical related applications. Additionally, recharging operations should interfere minimally with normal operations of devices that rely upon wireless power.